Curable compositions of an unsaturated bis-amide,a diamine,and a multicyclic aromatic compound

ABSTRACT

COMPOSITIONS CURABLE BY HEATING TO GIE RESINS OF GOOD HEAT RESISTANCE COMPRISE (A) A PREPOLYMER OF AN N,N&#39;&#39;BIS-IMIDE OF AN UNSATURATED DISCARBOXYLIC ACID AND A DIAMINE AND (B) AN AROMATIC COMPOUND OF 2 TO 3 BENZENE RINGS.

United States Patent Int. Cl. C08g 20/00 US. Cl. 260-78 U 8 ClaimsABSTRACT on THE DISCLOSURE Compositions curable by heating to giveresins of good heat resistance comprise (a) a prepolymer of an N,N'-bis-imide of an unsaturated dicarboxylic acid and a di amine and (b) anaromatic compound of 2 to 3 benzene rings.

in which D represents a. divalent radical containing a carbon-carbondouble bond and A is a divalent radical containing at least two carbonatoms, with a diprimary diamine of the formula: w

in which B represents a divalent radical of not more than 30 carbonatoms. The amounts of N,N'-bis-imide and of diamine are so chosen thatthe ratio No. of mols of bis-imide (I) No. of mols of diamineY(II) is atleast equal to 1; it is also generally preferred that the ratio shouldbe less than 50. Heat-resistant resins are obtained, which areremarkably resistant to severe heat stresses. 1

It is also indicated in French Pat. 1,555,564 that these resins can beprepared in bulk, by heating the previously intimately mixed reagents,or in an inert polar diluent such as dimethylformamide,N-methylpyrrolidone or dimethylacetamide, it being possible to use thelatter process where, for example, it is necessary to use a solution ofthe polymer formed.

Finally, it is mentioned in the said patent that for numerous uses it isadvantageous to carry out the process in two steps. In a first stage, aprepolymer is prepared by heating an intimate mixture of the tworeagents of Formulae I and II to a temperature of the order of 100 to250 C. The resulting prepolymer can be used in the form of a solution, asuspension or a powder, or can also be shaped by simple casting whilehot. In a second stage, the curing of the prepolymer can be broughtabout by further heating to temperatures of the order of 350 C.,optionally under pressure.

The present invention provides compositions which can be cured to giveheat-resistant resins, comprising (a) a Patented July 25, 1972prepolymer obtained by heating an N,N'-bis-imide of the formula:

in which D represents a divalent organic radical containing acarbon-carbon double bond and A represents a divalent organic radicalcontaining at least two carbon atoms, with a diprimary diamine of theformula:

in which B represents a divalent organic radical of not more than 30carbon atoms, and (b) an aromatic compound containing 2 to 4 benzenerings, which does not sublime or boil at atmospheric pressure up to 250C.

The radical D is derived from an anhydride of a dicarboxylic ethylenicacid of the formula:

1 co. (III) which can be, for example, maleic anhydride, citraconicanhydride, itaconic anhydride, pyrocinchonic anhydride,tetrahydrophthalic anhydride, dichloromaleic anhydride as well as theDials-Alder reaction products of one of these anhydrides with anacyclic, alicyclic or heterocyclic diene, e.g. cyclopentadiene. Asregards the anhydrides resulting from a dieue synthesis, reference canfor example be made to volume IV of the work entitled Organic Reactions(John Wiley and Sons, Inc.)

The symbols A and B may be identical or different and may representlinear or branched alkylene radicals having less than 13 carbon atoms ora phenylene, cyclohexylene,

The symbols A and B can also contain several phenylene or cyclohexyleneradicals linked to one another by a simple valency bond or by an inertatom or group, such as 0-, -S-, an alkylene grouping having 1 to 3carbon atoms,

X v 0 I wherein R represents a hydrogen atom, an alkyl radical having 1to 4 carbon atoms or a phenyl or cyclohexyl4,4'-diamino-dicycloheirylmethane,

radical, and X representsaualkylene radical having fewer than llf carbonatomsor a pheuyler e or cycloheztylene radical. The various phenylene orcyclohexylene radicals can furthermore be substituted by methylgroupings.

N,N'-ethylene-bis-maleimide, N',N'rhexamethylene-bis-maleimide, N,N'-metaphenylene-bis-maleimide,

- N,N'-,paraphenylene-bis-maleimide,

N,NQ4,4diphenylmethane-bis-maleimide, N,-N4,4'-diphenylether-bismaleimide,

N,N'-4,4'-diphenylsulphone-bis-maleimicle,

N,N'-4,4'dicyclohexylmethane-bis-maleimide, I N,N-an;'-4,4'-dimethylenecyclohexane-bis-maleimide,

.aN,Ni-meta-xylylene-bis-maleimide,r'

N,-N'-4,4'-diphenylcyclohexane-bis-maleimide, vN,N-metaphenylene-bis-tetrahydrophthali 'de and IN,Nf-4,4'-diphenylrnethane-bis-citraconimide. a

i .v These bisimides can be prepared by the method'described in US. Pat.No; 2,444,536 for'thepreparatio'li of N-arylmaleimides.

1,4-diamino-cyclohexane, I a 2,6Pdiamino-pyridine,

meta-phenylenediamine, para-phenylenediamine,

' 2,5-bis(p-aminophenyl)-1,3,4-oxadiaao1e, p 2,S-bis(rn-a.minophenyl)-thiazolo(4,5-d)thiazole, I ,1

'5,5'-di(m-aminophenyl) -(2,2') -bis-( LBA-OXadia ZOIyl4,4-bis(p-aminophenyl)-2,2'-bithiazole, m-bis(2-(4-p-aminophenyl)thiazolyDbenzene,2,2-bis(rn-arhinophenyl)-5,5'-dibenzimidazole} 4,4' diaminobenzanilide,phenyl-4,4'-diaminobenzoate,i1

' N,N'-bis(4-'aminobenzoy1)p-phenylenediamine, and

3,5 -bis (m-aminophenyl) -4-phenyl- 1,2,4-triazole.

To prepare the prepolymer (a), the amounts of bisimide ('I) andof,diamine (II) are so chosen that ,the ratio p v No. of mols of *bisirr'iid e No, of mols of diainine is greater-than land is preferablybetween-'1 preferablybetween 1:3 and .5.

The preparation of-th prepolymer ca be by heating the reagents,preferably at betigvee "'5 and 250 C. The reagents can be subjectedbare; a

intimate mixing which can,- '1epending onth hys'ical state'of thereagents in question, consist ofappiyiiigjthe" usual techniques formixing finely" divided o'l'id'si orfof By way of specific examples ofbis-imides I) there may 5 l bementioned': l

dissolving or dispersing one of the reagents inthe other, lgept, intheliguid state, The bis imideand the iamine can also be heated in achemicall y inert slvenfsiifi as cresol, dimethylformamide,N-methylpyrrolidone, dimethylacetamide or chlorobenzene. I

In the aromatic compound -(b), the benzene rings can,formyondensednucleL'or. th'eycan belinkedjo oneanother byjiyakncy,bond: or by-an inert atom or group it being understood that fin anyparticular compound the overall association of the'rings can .occur by acombination of these various types of association.

cially be quoted=the isomeric ter'phenyls;' the chlorinated diphenyls,"diphenyl oxide, 2,Z'-dinaphthyl "ox'ide,"- (ii-o1 methoxypherlyl oXide,be'nzophenon'e, 2,5;4 t'rimethylbenzophen'one, [p-phenylbenzophenone,

p-fluorobenzm phenone, diphenylamine, diphenylmethylamine,triphenylamine,": azobenzene, 4,4 -=-dimethyl-azobenzene, azoxybenzene,diphenylmetha nejLl diphenylethane, 1,1-diph'enylpropane,triphenylmethane', diphenylsulphone, di-

of= thegaromatic compound -(b).- f Then'ewcompositions can be preparedby producing 45" phen'ylsulphidfe, 1',2 L diphenylethane,p-diphenoxyb'enze'ne; 1,-1 diph'enyljphthalane, 1,1dipheriylcyclohexane, "pheny1 be'nzoate; benzyl benioate, p-nitrophenyl'terephthalate, beuaanilide and"phenanthrene. 1

The compositions according to the invention'cah' con- "20%,* by weightanwintimatemixture of the-prepo1ymer=(a) and thearomatic compound (b).Dependingon the physical" characteristics of the"ingreclients,'="operation can consist of i applying the f usual techniques for 'rnixingfiriely' divided tioned above.

solids or: ofdissolving or suspending-the aromatic com- (bl-"in theprepolymer, kept in theliquidfstate, optionally iii-(sneer thechemically solventis rii'en- In accordance with-a' preferredtechnique,'**theprecompositionL'Fo'r example,; the mixtur oftheprecursors oi? the prepolfis rii'erand the' aromatic coinpouiid fib')can be heated 10150" to 250? C. for from several minutesto several'l1of1rs3 tIt 1 advantageousto heat the 11am a=- homegneeasqiquia istitainedwhiehcan beused 'sitidnseah'be'eure b'y sting Whilst hot,

:s ueimoaexampl shaped sgf many -'rioticeable in the case of 1 articl veempaaaa is "th moulded rrain pewders.

devoid? of the aromatic ompos-itronsaccord'ing to 'the invenftaeld artices 'Iiich,'*aft ingfare evenmo'reresistar'i to heat'st'ress'es of ltnguratio "Ihis -isfpiaiticcompressioncompared with P e ay the aromatic"compounds" fis' also of Wm? PRPF-PW Q n s t afl w ch nt to -be"-shap efdstate; because my allov'v the period during which the prepolymer can beused in the fused state to be extended. This advantage is of great valuein certain techniques, especially for moulding by;

casting. At the same time, the resins obtained after curing are stillremarkably resistant to heat stresses.

The examples which follow illustrate the invention.

EXAMPLE 1 A composition is prepared by intimately mixing 89.5 g. ofN,N-4,4'-diphenylrnethane-bis-maleimide with 19.8 g. ofbis(4-aminophenyl)methane and 5.8 g. of terphenyl containing 75% ofmeta-isomer and 25% of orthoisomer,

The mould is placed between the platens of a press previously heated to250 C. and the Whole is compressed under a pressure of 150 kg./cm. After1 hour, the article is removed from the mould while hot and then cutinto samples (length, 37.5 mm.; width, 9.57 mm.) which at 25 C. show afiexural breaking strength of 13.6 kg./ mm. for a span of 25.4 mm. Afterheating for 2000 hours at 250 C., this strength is still 12.9 kg./mm.

If the process is carried out without terphenyl under otherwiseidentical conditions, the article has a strength of 9.9 kg/mm. after thesame heating period.

EXAM PLE 2 This example illustrates the influence of various polycyclicaromatic compounds on the variation in the viscosity of homogeneouscompositions prepared from 26.85 g. ofN,N-4,4'-diphenylmethane-bis-maleimide and 5.94 g. ofbis(4-aminophenyl)methane and the aromatic compound used at the rate of3.64 g. or 8.19 g., respectively representing 10% and by weight based onthe total weight of the composition.

The various operations are carried out under otherwise identicalconditions. In each operation, the container containing the mixture isheated in a fluid kept at 150 0.; the mixture melts and its viscositythen increases gradually as a function of the time. For each additive inquestion, the time At is determined which elapses between starting theheating and the moment at which the viscosity of the mixture reaches 10poises. The precision of the test is of the order of half a minute.

This example also shows that the mechanical properties of the mouldedarticles obtained from compositions containing these aromatic compoundsremain excellent following heat stresses of long duration. Thesearticles were obtained by casting the composition in a mould heated to200 C.; the whole then being kept at this temperature for 2 hours; thearticle was removed from the mould at 150 C. and then subjected to asupplementary heat treatment of 48 hours at 250 C.

Table 1 summarises the results obtained.

a 6 EXAMPLE 3 This example also illustrates the influence of variouspolycyclic aromatic compounds on the change in the viscosity ofhomogeneous compositions prepared from 5.37 g. ofN,N-4,4'-diphenylmethane-bis-maleimide, 1.186 g. ofbis(4-ami11ophenyl)methane and the aromatic compound used at the rate of0.72 g., representing 10% by weight relative to the weight of thecomposition.

The conditions under which the operations are carried out are otherwiseidentical to those described in Example 2.

Table 2 summarises the results obtained.

7 TABLE 2 Nature of the aromatic compound: At (mins.) 1 Without aromaticcompound 13 Benzyl benzoate 22 Chlorinated diphenyls 1 21 Benzanilide 26Triphenylamine 30 N-methyldiphenylamine 27 Triphenylmethane 27 Diphenyloxide 29 Azobenzene 46 1 Mixture of chlorinated diphenyls marketed underthe name Pyralene 1199."

We claim:

1. A composition comprising:

(a) a prepolymer obtained by heating at a temperature from 50 to 250 C.a bis-imide selected from the group consisting ofN,N-ethylene-bis-maleimide, N,N-hexamethylene-bis-maleimide, N,Nmetaphenylene-bis-maleimide, N,N-paraphenyl-bis-maleimide, N,N 4,4diphenyl-methane-bis-maleimide, N,N- 4,4'-diphenylether-bis-maleimide,N,N 4,4dicyc10- hexylmethane-bis-maleimide,N,N-a,u-4,4'-dimethylenecyclohexane-bis-maleimide,N,N-metaxylyenebis-maleimide, N,N'-4,4-diphenylcyclohexane bismaleimide,N,N metaphenylene bis tetrahydrophthalimide, N,N-4,4-dipheny1sulphonebis maleimide, and N,N'-4,4-diphenylmethane-bis-citraconimide, with adiamine selected from the group consisting of4,4'-diamino-dicyclohexylmethane, 1,4-diamino-cyclohexane,2,6-diamino-pyridine, meta-phenylenediamine, para-phenylene-diamine,4,4-diaminodiphenylmethane, 2,2 bis (4-amino-phenyl) propane, benzidine,4,4-diaminophenyl oxide, 4,4-diaminodiphenylsulphide,4,4'-diaminodiphenylsulphone, bis- (4 aminophenyl)methylphosphine oxide,bis(4- aminophenyl)phenylphosphine oxide, bis(4-aminophenyl)methylamine,1,5-diamino-naphthalene, metaxylylenediamine, para-xylylenediamine,1,1-bis(paraaminophenyl)phthalane, hexamethylenediamine, 6,6'-diamin0-2,2'-dipyridyl, 4,4-diaminobenzophenone,4,4-diaminoazobenzene, bis(4-aminophenyl)phenylmethane,1,1-bis(4-aminophenyl)-cyclohexane, 1,1-

l Mixture containing 13% of ortho-isomer, 62% of meta-isomer and 25% ofpara-isomer, by

weight.

bis(4 amino-3-methylphenyl)-cyclohexane, 2,5-bis i (m-a.minophenyl 1,3,4oxadiazolc, 2,5-bis(p-aminophenyl)-1,3,4-oxadiazole, 2,5bis(m-aminophenyl)- thiazolo(4,5 d)thiazle, 5,5 di(m-aminophenyl)-(2,2')-bis-(1,3,4-oxadiazoly1), 4,4-bis(p-aminophenyl)-2,2-bithiazole,m-bis(2-(4-p-aminophenyl) thiazolyl)benzene, 2,2-bis-(m-aminophenyl) 5,5dibenzimidazole, 4,4'-diaminobenzanilide, phenyl, 4,4- diaminobenzoate,N,N'-bis(4-aminobenzoyl)p-phenylenediamine, and3,5-bis(m-aminopheny1)-4-phenyl-1,2,4-triazole; and

(b) an aromatic compound containing 2 to 4 benzene rings, which does notsublime or boil at atmospheric pressure up to a temperature of 250 C.,in which the benzene rings are condensed or are linked to one another bya valency bond or by a from:

the benzene rings being unsubstituted or substituted by methyl, methoxy,fluorine, chlorine or nitro radicals, the proportion by weight of saidaromatic compound being from 2% to 20% 2. A composition according toclaim 1 in which the aromatic compound is an isomeric terphenyl, achlorinated diphenyl, diphenyl oxide, 2,2'-dinaphthyl oxide,dio-methoxyphenyl oxide, benzophenone, 2,5,4'-trimethylbenzophenone,p-phenylbenzophenone, p-fluorobenzo-phenone, diphenylamine,diphenylmethylamine, triphenylamine, azobenzene,4,4'-dimethyl-azobenzene, azoxybengroup selected zene, diphenylmethane,1,l-diphenylethane, 1,1-diphenylpropane, triphenylmethane,diphenylsulphone, diphenylsulphide, 1,2-diphenylethane,p-diphenoxybcnzene, 1,1-diphenylphthalene 1,1-diphenylcyclohexane,phenyl benzoate, benzyl benzoate, p-nitrophenyl terephthalate,benzanilide or phenanthrene.

3. A cured product obtained by heating a composition as claimed in claim2 at 150 to 350 C.

4. A composition according to claim 1 in which the ratio of saidbis-imide to said diamine is from 1.3:1 to 5:1.

5. A composition according to claim 1 in which the prcpolymer isobtained from N,N-4,4'-diphenylmethanebis-maleimide and4,4-diamino-diphcnylmethane.

6. A composition according to claim 1 in which the aromatic compound isa terphenyl.

7. A composition according to claim 1 made by heating the saidN,N'-bis-imide with the said diamine in the presence of the saidaromatic compound at to 250 C.

8. A cured product obtained by heating a composition as claimed in claim1 at to 350 C.

References Cited UNITED STATES PATENTS 2,55 0,650 4/1951 Arnold 260-33.83,384,615 5/ 1968 Agovri et a1. 260-45.9 3,4181267 12/1968 Busse 26033.83,452,056 6/ 1969 Sundholm 260-45.9 3,562,223 2/1971 Bargain et al.260-78 3,533,996 10/1970 Grundschober et al. 260-78 X OTHER REFERENCESEncyclopedia of Chemical Technology, Kirk et al., pp.

